Wick type writing instrument



Dec. 24, 1968 w. H. DERBINS WICK TYPE WRITING INSTRUMENT Filed Nov. 29, 1965 INVENTOQ WILLIAM H. DERBINS United States Patent Office 3,418,056 Patented Dec. 24, 1968 t 3,418,056 WICK TYPE WRITING INSTRUMENT William H. Derbins, Janesville, Wis., assignor to The Parker Pen Company, Janesville, Wis., a corporation of Wsconsm y l Filed Nov. 29, 1965, Ser. No. 510,329

Claims. (Cl. 401-199) ABSTRACT oF THE DISCLOSURE vThe present invention generally relates to a wick-type writing instrument or pen for applying a liquid-type ink to a writing medium, and it relates more particularly to a writing instrument having a self-contained cartridge assembly including a writing wick and associated reservoir which is removably mounted'in a barrel member.

Writing wicks for wick-type writing instruments are generally formed of plastic filaments or particles closely compacted together to provide a plurality of interconnected capillary -passageways for conveying ink from one end of the wick to the other such that ink flows from the reservoir connected to one end of the Wick to the writing medium as the nib end of the wick is drawn thereacross.

Writing inks conventionally employ a liquid carrier such, for example, as water, and a colorant such as a pigment or dye. Accordingly, when the liquid carrier evaporates, the residue is primarily the colorant. When evaporation takes place within a Wick, the colorant residue tends to block or clog the capillary passageways and results in a deterioration of the wick for writing purposes. Obviously, the greater the percentage of colorant in the ink and thus the darker the ink, the greater the rate of deterioration of the wick. Writing wicks thus have a predeterminable life span which varies with the type of ink used.

Another important characteristic of writing wicks is the size of the capillary passages therein, and since inks vary in terms of flow characteristics, it has been found that for maximum efficiency the ink and the writing wick should be matched to one another. The same wick will operate better with one type of ink than another.

A principal object of the present invention is to provide a new and improved wick-type writing instrument or pen.

Another object of the present invention is to provide a new and improved writing instrument incorporating a replaceable wick-type cartridge assembly including an integral ink reservoir.

In accordance with one feature of the present invention, there is provided an inexpensive wick-type of cartridge in which the wick and the ink are matched to one another and which is designed to be discarded when the supply of ink has become exhausted. This cartridge iS adapted to be used with a permanent barrel assembly in which the cartridge is removably mounted so that replacement thereof may be readily made.

Further objects and advantages and a better -understanding of the present invention may be had by reference to the following detailed description taken in conjunction with the accompanying drawing, wherein:

FIGURE lA is an enlarged longitudinal sectional view of the forward portion of a writing instrument embodying the present invention;

FIGURE 1B is an enlarged longitudinal sectional view of the rearward portion of the writing instrument shown in FIG. lA;

FIGURE 2 is a cross-sectional view of the ink cartridge portion of the device of FIG. 1A taken across the line 2*-2 thereof;

FIGURE 3 is a cross-sectional view of the ink cartridge portion of the device of FIG. 1A taken along the line 3 3;

FIGURE 4 is a cross-sectional longitudinal View of the forward portion of the ink cartridge of FIGS. 1A and 1B with a protective cap secured thereover; and

FIGURE 5 is a fragmentary view of another embodiment of the present invention.

Referring now to the drawing, and more particularly to FIG. 1A thereof, there is shown a wick-type writing instrument 10 comprising a tubular forward barrel member `12, preferably formed of a suitable plastic material, which is provided with an internal thread 14 at its forward end and an external thread 16 at its rearward end. An annular recess or rabbet 18 is provided forward of the external thread 16 and receives a metallic trim band 20 which is tightly fitted and secured in place over the barrel member 12. A rear barrel member 22 is provided at its forward end with an internal thread 24 which engages the thread 16 on the forward barrel member 12 to removably connect the barrel parts 12 and 22 together. The rear end of the barrel part 22 is closed by a wall 26.

In order to facilitate manufacture of the pen 10, and for esthetic reasons, a generally tubular point member 30 is provided. The point member 30 tapers inwardly in a forward direction and includes an axial bore 32 and a rearwardly disposed counterbore 34. The point member 30 is secured to the barrel member 12 by means of a rearwardly extending portion 36 of lesser diameter than the main body portion 'and which is externally threaded for mating engagement with the internal threads 14 at the forward end of the barrel part 12. As shown, an annular, external shoulder 38 is provided forwardly of the threaded part 36 for mating engagement with the forward end of the barrel part 12 when the parts are assembled.

The pen parts 12, 22, and 30 thus define a generally cylindrical chamber in which is mounted a -wick cartridge 40. The cartridge 40 is `an integral unit and includes a porous writing wick 42, preferably formed of plastic, which extends from the forward end of a cartridge body or housing. The housing consists of a forwardly disposed tubular portion 44 formed of plastic, and a rear tubular portion 46 also preferably formed of plastic and which is fitted into the rear of the housing member 44 and sealably closed at its rearward end by means of an integral imperforate wall 48.

Considered in greater det-ail, the cartridge housing mem- Iber 46 has a forwardly extending tubular portion 50 of reduced external diameter which defines a `forwardly facing, external annular shoulder 52. The rearward end of the forward housing member 44 is enlarged as shown at 54 to tightly fit over the tubular portion 50 so that the rearward end thereof abuts the shoulder 52. During assembly of the cartridge, the housing parts 44 and 46 are preferably heat-sealed together into a fixedly connected, integral unit. It will be noted that an annular space 56 is provided between the forward end of the housing part 46 and a tapered annular shoulder 58 on the forward housing part 44. As the description proceeds it will be seen that the provision of this annular space `facilitates assembly of the members 44 and 46 together.

In order to hold the wick in the cartridge 40, the forward portion 60 of the cartridge housing part 44 is reduced in size and has a cylindrical inner area having a diameter slightly less-than theunst-ressedexternaldiameter of the wick 42 whereby the wick 42, which is somewhat resilient, is frictionally held within the cartridge. Intermediate the wick gripping portion 60 and the main reservoir portion of the cartridge housing part 44, there is provided an intermediate tubular portion 62 having an external dameter greater than that of the forward portion 60 but substantially less than that of the main body portion of the housing part 44 thereby to define an annular, forwardly rfacingshoulder 64 located within the barrel part 12 rearwardly of the point member 30. The intermediate part 62 is provided therein with a transverse hole 66 for conveying replacement -air to the reservoir. Such air is supplied to the hole 66 from the ambient atmosphere through the annular space between the wick gripping portion 60 of the cartridge and the wall of the bore in the point member 30. As shown, the hole 66 connects directly into a relatively large, noncapillary air feed groove 68 defined between a pair of longitudinally extending ribs 70 and 72 provided on the inner wall of the cartridge housing part 44. The groove 68 has a sufficiently large cross-sectional dimension such that the ink with ywhich the pen is adapted to be used through into the reservoir to replace the ink as it is written out. As best shown in FIGS. lA and 1B, the groove 68 is continuous and extends from a location forward from the hole 66 and opens near the lrear end of the housing part 44 into the annular space 56.

A similar non-capillary `groove 69 is provided in the rear housing member 46 between a pair of longitudinal ribs 71 and 73. The groove 69 is thus adapted to feed air to the rear of the reservoir from the annular space S6. The space 56 thus eliminates the need for aligning the grooves 68 and 69 when assembling the parts 4.4 and 46.

In order toI hold ink in the reservoir within the housing parts 44 and 46, to the wick 42, there is provided a generally cylindrical capillary element 70 in the form of a bundle of compacted filaments of cellulose acetate or the like. The element 70 has a multiplicity of capillary passageways extending therethrough wherein the ink is stored. One such element is described in U.S. Patent No. 3,111,702, issued to Berger. It is important, however, that the element not extend into the groove 68 thereby to insure a non-restricted air return path for the reservoir.

In order to feed ink to the wick 42, the rearward end 42a thereof abuts tightly against and may :be pressed slightly into the forward end'of the reservoir element 70 thereby to provide a tight capillary fit between the elements whereby ink will flow from the reservoir element 70 into the wick -42 as ink is written out of the wick.

In order to prevent movement of the cartridge 40 within the barrel of the pen, an annular forwardly facing shoulder 74 is provided in the inner wall of the rear barrel part 22 and provides a seat against which the rearward end of the forward cartridge housing part 44 labuts. A coil spring 75 is compressed between the forwardly facing shoulder 64 on the for-ward cartridge housing part 44 and the rear face of the point member 30 thereby to resiliently urge the cartridge rearwardly into a fixed position against the shoulder 74. The spring 75 instrument housing, an imperforate sealing cap 78 is pressfitted over the cartridge portions 60 and 62 thereby to tightly seal the wick and the reservoir yfrom the atmosphere.

In FIG. 5 there is shown an alternative embodiment of the invention. In the pen of FIG. 5 a coil spring 80 is lplaced in the barrel part 22 behind the cartridge part 46 -and urges the cartridge 40 forwardly such that the V'shoulder 64 thereon abuts the rearendof the point member 30. This embodiment of the invention has the advantage of preventing the user from exerting on the wick a force exceeding that of the spring 80. Accordingly, by matching the pressure ofthe spring 80 to the strength of the associated wick, wick life is enhanced. As'a further alternative, the ink cartridge maybe firmly but removably connected to the barrel member 12 by cooperating threaded sections on the outside of the cartridge and the interior of the barrel member.

While there have been described what are at present believed to be the preferred embodiments of the invention, it will be understood that various changes and modifications may be made therein; and it is contemplated to cover in the appended claims all such changes and modificationsas fall within the true spirit and scope of the invention. A

What is claimed is. v t f 1. A self-contained wick type writing cartridge adapted to be removably mounted in a housing barrel and comprising Y ,y y

an elongated tubularhousing member formed vof an imperforate material and being closed at the rear end and open at the front end thereof,

the forward portion of said member being necked down to provide an elongated wick receiving portion,

a writing wick press-fitted into said wick receiving p0rtion, l

said wick and said wick receiving portion having complementary mating surfaces whereby said wick receiving portion is completely filled with said wick,

said writing cartridge being provided with a plurality of longitudinally extending internal walls extending rearwardly from a location near said necked down portion to define an air replacement channel.

said member having a transverse aperture therein opening into the air replacement channel, and

an ink retaining capillary filler material substantially filling the rearward portion of said member and abutting said air replacement channel.

2. A cartridge as set forth in claim 1v wherein said rear end of said member is closed by `a generally tubular, imperforate Ycasing closed at one end with the other end sealably fitted into the rearward end of said housing member,

a firstplurality of longitudinally extending internal walls within said housing member and a second plurality of longitudinally extending internal vwalls within said casing defining therebetween said air replacement channel, and

said casing and said housing member defining an annular chamber interconnected between a portion of the air replacement channel in saidvcasing yand a portion of the air replacement channel in said housing member.

3. A cartridge as set forth in claim 1 wherein said housing member includes an enlarged rearward portion in which said fillermaterial is disposed, v

an intermediate portion disposed between said wick receiving portion and said enlarged portion,

said internal walls including a plurality of longitudinally extending ribs on the internal walls of said housing and casing and said air replacement channel extending into said intermediate portion in engagement with said wick.

4. A wick type writing instrument comprising a barrel assembly having a pair of mutually disassemblable front and rear parts defining an elongated cavity,

said fro'nt part being open at the front, and

a self-contained wick type cartridge according to claim 1 removably mounted in said cavity with said wick extending through the opening at the front end 0f said barrel.

5. A wick type writing instrument according to claim 2,392,840 1/ 1946 De Groft 15-537 4 further comprising 2,554,654 5/ 1951 Wittnebert 120-501 la spring means mounted in said barrel for resiliently 3,088,160 5/1963 Cline 15-563 urging said wick outwardly of said barrel, 3,221,360 12/ 1965 Seeman 15-537 whereby said spring means is compressed by the force 5 FOREIGN PATENTS exerted on said wick during writing.

References Cited UNITED STATES PATENTS 3,181,539 5/1965 Aston 401-188 10 U.S. Cl. XR. 3,332,400 7/1967 Sonntag 401-132 XR 401--276 3,355,239 11/1967 Albrecht 401--148 1,006,596 1/ 1952 France.

ROBERT W. MICHELL, Primary Examiner. 

